Mac: Turn on tab overview mode by default.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 65f40a80290043304b828bc97256e18230a5fe4c..e26a4f187ca3d03c00961b43cbacb5f58955dbcf 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -1355,9 +1355,6 @@ const char kPasswordStore[]                 = "password-store";
 // has been out there for a few dev channel releases without problems.
 const char kDisableHolePunching[]           = "disable-hole-punching";
 
-// Enables the tabs expose feature ( http://crbug.com/50307 ).
-const char kEnableExposeForTabs[] = "enable-expose-for-tabs";
-
 // Cause the OS X sandbox write to syslog every time an access to a resource
 // is denied by the sandbox.
 const char kEnableSandboxLogging[]          = "enable-sandbox-logging";